1. Field of the Invention
The present invention is related to piping systems for installing gas service from a gas distribution main pipeline to a residential or commercial gas inlet connection, and more particularly to a gas service completion kit for conveniently fabricating and rapidly installing such gas service.
2. Description of the Prior Art
It is well known that natural gas is a clean and relatively inexpensive fuel source. As such, gas distribution systems have been widely installed in various population centers throughout the United States and many other countries of the world. To supply and provide gas service to end users, such as commercial and residential consumers, service pipelines are typically branched from main gas distribution pipelines laid along a utility route, for instance, under a roadway. These service pipelines typically incorporate an above ground shut-off valve, a pressure regulator for stepping down gas pressure to a gas meter and there from the meter is plumbed to a gas inlet connection pipe typically stubbed outwardly from a side wall of the dwelling or facility.
Safety regulations require that any exposed service pipe be metallic in nature to provide sufficient rigidity and structural integrity for supporting the pressure regulator and gas meter while providing protection against damage and possibility of rupture should such pipe be accidentally contacted by sharp or hard objects. Buried underground gas transmission service pipes, however, may be composed of plastic materials, such as polyethylene plastic tubing since such underground plastic tubing runs a lesser risk of accidental contact from a hard object. Plastic tubing is desirable because it is relatively inexpensive to manufacture, resistant to corrosion and requires less labor for installation.
Therefore, the industry has adopted the use of metallic L-shaped gas meter riser pipes incorporating transition couplings to transition from underground plastic tubing to the above ground metallic pipe. Typically, the riser pipe is telescoped over a length of plastic tubing so that one end of the plastic tubing is disposed within the upper end of the riser pipe. Thereafter, the end of the plastic tubing may be plasticly deformed using any one of various styles of compressive fittings to form a fluid tight joint between the riser pipe and the plastic tubing. The opposite end of the plastic pipe typically projects a short distance from the opposite end of such riser, for instance twelve inches, to provide what is often termed a pigtail for connection to an intermediate length of plastic pipe which will lead to the subterranean distribution main pipe. Such riser pipes are usually prefabricated at a factory site for subsequent installation by service line installers. While there have been some instances in the past when prior art risers have, for special applications, been formed with long plastic pipe pigtails, more typically the riser assemblies fabricated in a factory setting have been constructed with relatively short pigtails, on the order of 10-12 inches in length.
Installation of such service distribution system pipelines typically involves a route where a series of such service lines are to be installed, for instance at a new housing tract. As such, an installation crew, of perhaps three or more members, attends to installation along the route. Typically, the installers use various conventional pipe fittings to effectuate the installation of the riser pipe, pressure regulator, shut-off valve, and gas meter. Therefore, a heavily ladened, heavy-duty truck carrying lengths of pipe, pipe cutters, pipe threaders, electric generators, plastic pipe fusion butt welders, and pipe wrenches, as well as other tools, accompany such crew to the site. As well known to those skilled in the art, such a truck and tools are very costly.
Once the crew has arrived to the installation site, a factory assembled riser pipe and various lengths of threaded short nipples, elbows, union fittings, and the like, including a shut-off valve, pressure regulator, and a gas meter are selected for assembling the service connection. Typically, the upper end of a factory fabricated riser pipe is threaded to a shut-off valve and a series of short threaded nipples and coupling unions are threadedly coupled from the valve to a gas regulator. Thereafter, a series of alternating nipples and elbow fittings are threadedly joined to form a turned back U assembly. The end of the turned back U assembly is coupled to a threaded union fitting for attachment to a gas meter. From the outlet fitting of the gas meter, another union fitting and a series of nipples and elbow fittings are threadedly joined and therefrom another union fitting is connected to a stubbed inlet connection at the residence. During the assembly of such piping configuration, each threaded connection is coated with a Teflon pipe sealant or pipe dope prior to threading. A free end of the pigtail of plastic tubing extends from the bottom of the riser pipe and is fusion butt welded to an intermediate length of plastic tubing, the opposite end thereof connected to a tee fitting at the gas distribution main. Thereafter, the above ground portion of the completed service line assembly is coated with paint or a rust inhibitor. It is to be appreciated that the assembly time required to perform such assembly operation may be on the order of about thirty minutes.
Once the service line assembly is completed, regulations require that such assembly be pressurized to a predetermined pressure and leak tested prior to such service line assembly being brought into service. Such leak testing operations typically take on the order of about thirty to forty minutes. Therefore, it is to be appreciated that the complete installation time for a single service line may take on the order of an hour, involving two to three man-hours which proves to be very costly at today's labor rates.
In addition, it has been found that the effectiveness of the rust inhibitor or paint coating deteriorates over time causing threaded connections to leak which may result in possible dangerous conditions and increased gas usage.
Hence, those skilled in the art have recognized the need for improving the method of fabricating the required components for field installation to facilitate convenient and efficient installation of gas service to end users while minimizing installation labor costs. There is a need for a kit that incorporates a minimum number of components to lower manufacturing costs while facilitating ease of factory assembly. Such a kit should reduce the need for heavy-duty field installation tools and should eliminate the need to assemble an extensive number of pipe fittings in the field. Furthermore, such a kit should offer a construction that reduces the possibility of corrosion and rust over the life of the system. In addition, such a gas service completion kit should be packaged in a compact package for convenient handling, storage, shipment and transport to the field. The present invention meets these needs and others.